1. Technical Field
The present invention relates to color filter substrates, liquid crystal units, and electronic devices.
2. Related Art
Transflective liquid crystal units are known, which have both transmissive display regions for display with light from an artificial light source and reflective display regions for display with external light such as sunlight. These liquid crystal units consume a smaller amount of power than transmissive displays, which must continuously keep a light source on, because they can provide sufficient visibility for display in a dark place and utilize external light for display in a light place.
In the transmissive display mode of transflective liquid crystal units, light from a backlight passes through color layers of a color filter only once to exit to the viewer side. In the reflective display mode, on the other hand, external light passes through color layers of a color filter before and after being reflected by a reflective member, namely twice in total, to exit to the viewer side. As a result, external light and light from a backlight have different densities after passing through color layers. The color layers of transflective liquid crystal units therefore require a larger thickness in the transmissive display regions than in the reflective display regions to inhibit the difference in color between the transmissive display and the reflective display and thereby achieve a uniform density. In addition, three color layers corresponding to red, green, and blue must be provided in both transmissive display regions and reflective display regions to provide full-color display; therefore, photolithography must be performed six times in total to form color layers of the three colors with different thicknesses in the transmissive display regions and the reflective display regions.
Recently, JP-A-2003-161933, for example, has proposed a transflective liquid crystal unit having transmissive display regions each of which includes stacked color layers of two colors selected from the group of cyan, yellow, and magenta and reflective display regions each of which includes two different color layers arranged in a single layer. This liquid crystal unit can mix two colors selected from the group of cyan, yellow, and magenta to provide red, green, and blue display colors; therefore, this unit requires half the number of photolithography steps.